Ask away! (You may, if you wish, ask multiple questions (perhaps of multiple characters) or attempt to engage the characters in extended conversation.)
As for characters, I am very comfortable with Hakkai, Fye, Tokitoh, Hazel, Mokuba, and Ed.
Anyone I've written before, however, is fair game! Please, play away!
[EDIT] Oh, and feel free to ask IC! Just tell me who you are XD;;;